//
// SharedLibrary.h
//
// $Id: //poco/1.3/Foundation/include/Poco/SharedLibrary.h#1 $
//
// Library: Foundation
// Package: SharedLibrary
// Module:  SharedLibrary
//
// Definition of the SharedLibrary class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//

#ifndef Foundation_SharedLibrary_INCLUDED
#define Foundation_SharedLibrary_INCLUDED

#include "platform.hpp"
#include <string>
#include <mutex>

namespace BT
{
class SharedLibrary
/// The SharedLibrary class dynamically
/// loads shared libraries at run-time.
{
  public:
    enum Flags
    {
        SHLIB_GLOBAL = 1,
        /// On platforms that use dlopen(), use RTLD_GLOBAL. This is the default
        /// if no flags are given.
        ///
        /// This flag is ignored on platforms that do not use dlopen().

        SHLIB_LOCAL = 2
        /// On platforms that use dlopen(), use RTLD_LOCAL instead of RTLD_GLOBAL.
        ///
        /// Note that if this flag is specified, RTTI (including dynamic_cast and throw) will
        /// not work for types defined in the shared library with GCC and possibly other
        /// compilers as well. See http://gcc.gnu.org/faq.html#dso for more information.
        ///
        /// This flag is ignored on platforms that do not use dlopen().
    };

    SharedLibrary();
    /// Creates a SharedLibrary object.

    SharedLibrary(const std::string& path, int flags = 0);
    /// Creates a SharedLibrary object and loads a library
    /// from the given path, using the given flags.
    /// See the Flags enumeration for valid values.

    virtual ~SharedLibrary() = default;
    /// Destroys the SharedLibrary. The actual library
    /// remains loaded.

    void load(const std::string& path, int flags = 0);
    /// Loads a shared library from the given path,
    /// using the given flags. See the Flags enumeration
    /// for valid values.
    /// Throws a LibraryAlreadyLoadedException if
    /// a library has already been loaded.
    /// Throws a LibraryLoadException if the library
    /// cannot be loaded.

    void unload();
    /// Unloads a shared library.

    bool isLoaded() const;
    /// Returns true iff a library has been loaded.

    bool hasSymbol(const std::string& name);
    /// Returns true iff the loaded library contains
    /// a symbol with the given name.

    void* getSymbol(const std::string& name);
    /// Returns the address of the symbol with
    /// the given name. For functions, this
    /// is the entry point of the function.
    /// Throws a NotFoundException if the symbol
    /// does not exist.

    const std::string& getPath() const;
    /// Returns the path of the library, as
    /// specified in a call to load() or the
    /// constructor.

    static std::string prefix();
    /// Returns the platform-specific filename prefix
    /// for shared libraries.
    /// Most platforms would return "lib" as prefix, while
    /// on Cygwin, the "cyg" prefix will be returned.

    static std::string suffix();
    /// Returns the platform-specific filename suffix
    /// for shared libraries (including the period).
    /// In debug mode, the suffix also includes a
    /// "d" to specify the debug version of a library.

    static std::string getOSName(const std::string& name);
    /// Returns the platform-specific filename
    /// for shared libraries by prefixing and suffixing name
    /// with prefix() and suffix()

  private:
    SharedLibrary(const SharedLibrary&);
    SharedLibrary& operator=(const SharedLibrary&);

    void* findSymbol(const std::string& name);

    std::string _path;
    void* _handle;
    std::mutex _mutex;
};

}   // namespace Poco

#endif   // Foundation_SharedLibrary_INCLUDED
